Bone Densitometry (DEXA, DXA)
Bone densitometry, also called dual-energy x-ray absorptiometry, DEXA or DXA, uses a very small dose of ionizing radiation to produce pictures of the inside of the body (usually the lower (or lumbar) spine and hips) to measure bone loss. It is commonly used to diagnose osteoporosis, to assess an individual’s risk for developing osteoporotic fractures. DXA is simple, quick and noninvasive. It’s also the most commonly used and the most standard method for diagnosing osteoporosis.
This exam requires little to no special preparation. Tell your doctor and the technologist if there is a possibility you are pregnant or if you recently had a barium exam or received an injection of contrast material for a CT or radioisotope scan. Leave jewelry at home and wear loose, comfortable clothing. You may be asked to wear a gown. You should not take calcium supplements for at least 24 hours before your exam.
- DXA bone densitometry is a simple, quick and noninvasive procedure.
- No anesthesia is required.
- The amount of radiation used is extremely small—less than one-tenth the dose of a standard chest x-ray, and less than a day’s exposure to natural radiation.
- DXA bone density testing is currently the best standardized method available to diagnose osteoporosis and is also considered an accurate estimator of fracture risk.
- DXA is used to make a decision whether treatment is required and it can be used to monitor the effects of the treatment.
- DXA equipment is widely available making DXA bone densitometry testing convenient for patients and physicians alike.
- No radiation remains in a patient’s body after an x-ray examination.
- X-rays usually have no side effects in the typical diagnostic range for this exam.
- There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
- Women should always inform their physician or x-ray technologist if there is any possibility that they are pregnant. See the Safety in X-ray, Interventional Radiology and Nuclear Medicine Procedures page for more information about pregnancy and x-rays.
- The effective radiation dose for this procedure varies. See the Radiation Dose in X-Ray and CT Exams page for more information about radiation dose.
- No complications are expected with the DXA procedure.
Discovery DXA System
The Hologic Discovery DXA system enables you to identify patients at risk for osteoporosis and other debilitating conditions. Delivering exceptional precision and pinpoint accuracy, Hologic Discovery DXA technology delivers high quality images for your at-risk patients.
OnePass single-sweep scanning, which delivers superb image quality8 and precision.9 Our exclusive design utilizes a multi-element digital detector array paired with true fan-beam acquisition geometry, enabling rapid, dual-energy bone density measurements. OnePass scanning is designed to eliminate beam overlap errors and image distortion found in rectilinear acquisition techniques, resulting in superb image quality and data stability.